Mechanism of nodularization of graphite in cast irons treated with magnesium

Yamamoto, S.; Chang, B.; Kawano, Yoichi; Ozaki, Ryosuke; Murakami, Y.

doi:10.1179/msc.1978.12.5.239

Cited by 16 publications

(5 citation statements)

References 1 publication

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“…This graphite structure is under the specifications of the nodular cast iron material according to the ASTM A 536 standard [27] which is carried out through an inoculation process. In this nodularization process, magnesium (Mg) alloy elements will be added to get a round of the graphite nodule so that the ductile iron base material can withstand tensile loads and impact loads according to researchs Sasaki et al [33] and Yamamoto S et al [34]. The microstructure found in the surface and the centre area is different.…”

Section: The Formation Of Microstructure At the Centre Zonementioning

confidence: 99%

Investigate Temperature Preheating on the Chill Plate to Identify Surface Characteristic on the Ductile Iron by Sand Casting

Guterres

Rusnaldy

Widodo

et al. 2021

IJEMM

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The chilled casting method is widely used in the metal casting industry to accelerate the mold's cooling rate. This method is very suitable for surface hardening by depositing the elements contained in the chill material onto the surface of the object being cast. One of the factors that influence surface hardness characteristics is the diffusion temperature. This study aims to determine the microhardness, surface layer thickness, and the element contained on the surface. The main material produced into Y-Block is ductile cast iron, the chill material is SS 304 plate with a thickness of 0.2mm. However, before the liquid material is poured into a mold, the chill plate is inserted into the surface of the pattern in the mold, then the plate was preheated. The result showed that the highest preheating temperature has produced microstructure around the surface area namely eutectic carbide of (FeCr)7C3, and (FeCr)3C. SEM-EDX analysis shows that 7.13%Cr is contained on the coating layer at a thickness of 0.020 mm and an average hardness of 700-900 HV.

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Section: The Formation Of Microstructure At the Centre Zonementioning

confidence: 99%

Investigate Temperature Preheating on the Chill Plate to Identify Surface Characteristic on the Ductile Iron by Sand Casting

Guterres

Rusnaldy

Widodo

et al. 2021

IJEMM

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show abstract

“…Further reasons for a lack of available magnesium may be a second oxidation during pouring, reaction with refractory 35 or fading out by floating of gas bubbles and metallic magnesium segregation at the austenite-residual melt interface. 36 Each chunky graphite segment has a face of the basal plane and a section of the prism face of the hexagonal graphite crystal. As per Itofuji, 34 chunky graphite dominantly grows along the a-axes of the hexagonal graphite crystal and helical growth does not exist.…”

Section: Formation and Growth Of Chunky Graphitementioning

confidence: 99%

Chunky Graphite in Ferritic Spheroidal Graphite Cast Iron: Formation, Prevention, Characterization, Impact on Properties: An Overview

Baer

2019

Inter Metalcast

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Ferritic spheroidal graphite cast iron (SGI) materials have a remarkable technical potential and economic impact in modern industry. These features are closely related to the question of how the cast materials can be produced without structural defects and graphite degenerations such as, for example, chunky graphite. Although the chunky graphite degeneration superficially seems to be well known, its metallurgical background is still controversially discussed, appropriate field-tested nondestructive tools for its quantification in castings are lacking, and the knowledge on its impact on material properties is fairly limited. Addressing this status, the article is providing a current overview on the subject. Existing theories on formation and growth mechanisms of chunky graphite are briefly reviewed. Furthermore, from a metallurgical point of view, causes for the appearance of chunky graphite as well as preventive measures are concisely summarized. Particular attention is paid to the morphology of chunky graphite and how it can be characterized by destructive and nondestructive techniques. Special emphasis was laid on providing a comprehensive overview on the impact of chunky graphite on strength, ductility, fatigue limit, fatigue crack growth rate as well as fracture toughness of ferritic SGI materials based on experimental data. Moreover, conclusions for the assessment of castings affected by chunky graphite are drawn.

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“…The growth of nodular graphite is different than that of FG. In addition to the heterogeneous nucleation theory 11 for the nodular graphite particles where a nucleus was seen, the bubble theory12, 13 was applied for the particles where no nucleus was found in the 2D section. According to the heterogeneous nucleation theory, nuclei form first themselves out of melt.…”

Section: Spheroidal Graphite Iron (Sg)mentioning

confidence: 99%

Characterization of Graphite Crystal Structure and Growth Mechanisms Using FIB and 3D Image Analysis

et al. 2010

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Considering the significant influence of the morphology of graphite inclusions on the properties of cast iron it is important to understand the correlation between manufacturing parameters and resulting microstructure. In particular, understanding the effect of alloying elements and inoculants on the formation and growth mechanisms of the graphite particles provides the basis for exact tailoring of the microstructure and thus exact tailoring of effective properties of cast iron. Experimental observations of the three‐dimensional (3D) structure of graphite particles, high resolution chemical analysis of nuclei and other inclusions, as well as quantitative characterization of possible growth mechanisms have confirmed certain existing theoretical models for nodular and flake graphite and provided a comprehensive description of all intermediate morphologies. Precise analysis of the graphite's crystal structure based on target preparation of transmission electron microscope thin foils opens additional possibilities for estimating of the properties of different graphite types.

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Mechanism of nodularization of graphite in cast irons treated with magnesium

Cited by 16 publications

References 1 publication

Investigate Temperature Preheating on the Chill Plate to Identify Surface Characteristic on the Ductile Iron by Sand Casting

Investigate Temperature Preheating on the Chill Plate to Identify Surface Characteristic on the Ductile Iron by Sand Casting

Chunky Graphite in Ferritic Spheroidal Graphite Cast Iron: Formation, Prevention, Characterization, Impact on Properties: An Overview

Characterization of Graphite Crystal Structure and Growth Mechanisms Using FIB and 3D Image Analysis

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